The present invention relates to a transport apparatus which transports a runner along a track while regulating the vertical position of runner wheels by means of the top and bottom of the track.
Conventional transport apparatuses of this type include, for example, a transport system using a linear induction motor. In this system, a reaction plate is attached to a runner which travels along a track. A plurality of stators are arranged at predetermined intervals along the track. Magnetic flux, which changes with time, is applied to the reaction plate which moves past the stators. The change of the magnetic flux produces a forward or reverse fixed impelling force in the reaction plate, thereby driving or stopping the runner.
In a transport system of this type, a plurality of runners may sometimes be run along the track. In this case, if one of the runners is stopped at any of the stators, the other runners cannot be run unless the stopped one is shunted from the track. Thus, it is imposssible to run a plurality of runners on practically the same track.
A measure to counter this problem has conventionally been proposed. It includes a shunting portion which is located at a position where the runner stops. Guide rails constituting a track, along with the runner, are partially shunted from the track to the shunting portion. The shunting portion is provided with spare rails which maintain the continuity of the track if the guide rails are partially shunted.
The prior art means arranged in this manner, however, requires an additional space and a mounting mechanism for the spare rails, thus increasing the size of the apparatus. At the shunting portion, moreover, the spare rails must undergo a delicate alignment or positioning, and the track is subject to joints. Thus, the runner cannot run smoothly.